Ischaemic bowel disease

Definition | Aetiology | Pathophysiology | Risk Factors | Signs and Symptoms | Investigations | Management

Definition

Ischaemic bowel disease refers to reduced blood flow to the intestines, leading to inflammation, injury, or necrosis. It includes mesenteric ischaemia (small bowel involvement) and ischaemic colitis (large bowel involvement).

Aetiology

  • Acute mesenteric ischaemia: caused by embolism (commonly from atrial fibrillation), thrombosis of mesenteric arteries, or low-flow states (shock, heart failure).
  • Chronic mesenteric ischaemia: atherosclerosis of mesenteric vessels causing intestinal angina.
  • Ischaemic colitis: hypoperfusion of the colon, often affecting the splenic flexure.

Pathophysiology

  • Reduced perfusion leads to ischaemic injury and inflammation.
  • Prolonged ischaemia causes mucosal necrosis, ulceration, and potential perforation.
  • Severe cases result in bacterial translocation, sepsis, and multi-organ failure.

Risk factors

  • Atrial fibrillation (risk of embolism).
  • Atherosclerosis.
  • Hypotension or shock.
  • Vasculitis (e.g., polyarteritis nodosa).
  • Hypercoagulable states (e.g., malignancy, thrombophilia).
  • Recent major surgery or trauma.

Signs and symptoms

Acute Mesenteric Ischaemia:

  • Severe, sudden-onset abdominal pain: out of proportion to examination findings.
  • Nausea and vomiting.
  • Diarrhoea or bloody stools.
  • Signs of sepsis or shock: hypotension, tachycardia.

Chronic Mesenteric Ischaemia:

  • Postprandial abdominal pain: "intestinal angina," typically 30–60 minutes after eating.
  • Weight loss: due to food avoidance.

Ischaemic Colitis:

  • Left-sided abdominal pain.
  • Bloody diarrhoea.
  • Low-grade fever.

Investigations

  • Blood tests:
    • Raised lactate (suggests bowel necrosis).
    • Leucocytosis and raised CRP (inflammation).
    • Coagulation screen (if hypercoagulable state suspected).
  • Imaging:
    • CT angiography (gold standard): identifies vascular occlusion or ischaemic changes.
    • Abdominal X-ray: may show thumbprinting (mucosal oedema) in ischaemic colitis.
    • Colonoscopy: identifies mucosal ulceration in ischaemic colitis.

Management

1. Initial Resuscitation:

  • IV fluids: aggressive resuscitation to restore perfusion.
  • Broad-spectrum IV antibiotics: to prevent bacterial translocation.
  • Pain management: IV paracetamol, opioids if needed.
  • Anticoagulation: if embolic mesenteric ischaemia is suspected (e.g., heparin infusion).

2. Specific Management Based on Cause:

  • Acute mesenteric ischaemia: urgent endovascular or surgical revascularisation.
  • Chronic mesenteric ischaemia: angioplasty and stenting if severe.
  • Ischaemic colitis: supportive care; surgery if perforation or necrosis occurs.

3. Surgical Intervention:

  • Laparotomy with bowel resection: if bowel infarction is suspected.
  • Endovascular stenting: for selected cases of mesenteric arterial stenosis.
GastroenterologymypanotesIschaemic bowel disease